TBI mods/help

[Gamikatsu]

OK...

my 89 K5 Jimmy (V1500 Jimmy but who cares) has a 5.7 TBI Motor in it... it runs quite healthy, does do a small puff of smoke when i start it up after sitting but thats negligable to me. I understand the motor has been gone through, but i don't know to what extent. I always will and have always, preferred a Carb over fuel injection. I am trying to squeaze some more oomf out of it... to help push the 35's with the tall gears its got. (3.42's factory). I know regearing it would probably help more than the motor but hey... it always needs more horsepower right? help me out on this one... what avenue should i take? In either scenario i will likely put a full engine kit in it... all rubber seals, check bearing clearances, probably throw a set of rings in it, new valve stem seals, and check valve guides. probably have a valve job done on it.

option 1
Stay TBI... do a 454 TBI, up the fuel pressure, throw a mild 4x4 style cam in it, and get a custom tune... eventually get a better set of heads.

Option 2
go carb... Edelbrock EPS square bore intake, Edelbrock 1407 700 CFM carb, Edelbrock 4x4/offroad style camshaft with lifters, and some tighter valve springs. for more capability in the RPM department.

I am up in the air on both of these... and i know the benefits of staying TBI over Carb.... but i'm having a hard time locating a 454 TBI locally....

 

[Southern Pride]

Honestly no HP mods you do to the motor can hold a candle to what a shorter gear like 4.56, would do. Plus you'll be tying up money in the motor for peanuts worth power and then your tranny says enough is enough.

 

[dirtridinz71]

I am trying to squeaze some more oomf out of it... to help push the 35's with the tall gears its got. (3.42's factory). I know regearing it would probably help more than the motor but hey...

You answered yourself right there. I noticed way more gain with 4.56 gears then I did with my mods. Better way to spend your money.

Though if you are set on it, no need for a 454 tbi with only a cam IMO. Im running a comp 249XE cam, edlebrock performer intake, with ultimate tbi mods, stock regular modified to be adjustable and running at 13psi. With a chip from Brian at TBIchips.com

 

[Blue95]

You answered yourself right there. I noticed way more gain with 4.56 gears then I did with my mods. Better way to spend your money.

Though if you are set on it, no need for a 454 tbi with only a cam IMO. Im running a comp 249XE cam, edlebrock performer intake, with ultimate tbi mods, stock regular modified to be adjustable and running at 13psi. With a chip from Brian at TBIchips.com

How is that running for you man?

and to the OP, deffinately re gear first, then go from there. make sure the truck is in good tune and all items up to *****.

 

[Southern Pride]

How is that running for you man?

and to the OP, deffinately re gear first, then go from there. make sure the truck is in good tune and all items up to *****.

Also curious I've been just now getting into modding and perfecting my motor. Really interested in the fuel pressure regulator where you can change the PSI. Just curious what that does, the gains, and how you like it?

 

[93Chevy_1500]

Also curious I've been just now getting into modding and perfecting my motor. Really interested in the fuel pressure regulator where you can change the PSI. Just curious what that does, the gains, and how you like it?

Im interested in the Fuel pressure regulator also.

 

[Southern Pride]

Im interested in the Fuel pressure regulator also.

Hey you should look into the thread in member trucks I think his name is blue95 or whatever but read his picture thread he has one and describes how affective it is and all that! Apparently these motors come lean from the factory and he matched his at 13 psi and said it made a good bit of difference, and wouldn't negatively effect mpg's! I've been reading about a good few different peeps talking about these lately. They must be worth it as you know these TBI motors are just dino-age worst design for flow so I'm sure anything that helps that makes a great difference along with the mods I did for top end power.

 

[dirtridinz71]

How is that running for you man?

and to the OP, deffinately re gear first, then go from there. make sure the truck is in good tune and all items up to *****.

Also curious I've been just now getting into modding and perfecting my motor. Really interested in the fuel pressure regulator where you can change the PSI. Just curious what that does, the gains, and how you like it?

Im interested in the Fuel pressure regulator also.

The truck runs great.

As for the making the stock FPR adjustable is simple. You need to remove the throttle body and then the regulator. On the bottom of it you should see where the stock 'bolt' is and you need to drill that out. Then JBweld a nut to the bottom of the regulator and I used a Allen head bolt (different from pictures). This will now let to to adjust the spring tension and fuel PSI.

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While you have the tb off you might as well grind of the ridges and make it smooth.

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And added a simple 0-15psi autometer fuel pressure gauge.

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[Southern Pride]

I wasn't even aware you made the stock one adjustable.

Isn't that grinding the ridges off the TB ports one of the ULTIMATE TBI MODS or whatever?? What does it do?

 

[GreaseDog]

yes, that is part of the ultimate tbi mods... however the pictured throttle body is only half done. the sharp corner left where the stock ridges were cut off needs to be radiused with a grinder. basically improves air flow around the injectors.